I discovered … new life on the bottom of the Southern Ocean

Everything down on the seafloor is amazing to me. When you think of Antarctica, you think of penguins, whales, sea and ice in a stark landscape. I love the charismatic megafauna but there are so many other interesting things in Antarctica – life on the seafloor rivals that of the Great Barrier Reef.

The view above the surface is quite monochrome but underneath the organisms are oranges, yellows, pinks – there is a coral that is psychedelic purple! Most tourists that go to Antarctica probably don’t know anything about the crazy, wacky communities on the sea floor – all of that intrigues me. It’s an explosion of colour, it really looks like an art gallery down there.

Video still of Stylasterid lace corals, sponge, crinoid, brittle stars seen during a submersible dive in the Bransfield Strait, Antarctica — A dive in the Bransfield Strait, Antarctica, reveals Stylasterid lace corals, sponge, crinoid and brittle stars. Photograph: Greenpeace

I have found more than a dozen new species on my trips to Antarctica, including many sea cucumbers, one of which was named after me. There is still so much to be discovered but it’s slow work for the taxonomists, and funding is scarce. On the last expedition with Greenpeace in 2022, we came across a community of tall, fragile barnacle that has yet to be described and may be years before it is actually classified.

I knew I wanted to be a marine biologist from the age of 15. I’m from Melbourne, and Australia has a long history with the Antarctic. I started volunteering at the local museum and was put to work on Antarctic sea urchins. I was hooked. Sea urchins brood their young in a little pouch near their mouth. They can have dozens of babies around them. On one female, I found 353 babies. It’s pretty cute – but I know not everyone would think that.

Susanne Lockhart at Windansea Beach in La Jolla — Lockhart has been studying Antarctic marine life for more than three decades. Photograph: Ariana Drehsler/The Guardian

My fascination and drive began with the puzzle, and working out what’s what. Sometimes, you have these organisms with characteristics that were described 100 years ago, but they can be wrong (Antarctic sea urchin taxonomy is a mess). Realising as a young person that these old revered scientists could be wrong – I found that compelling.

On my first expeditions in the 2000s, I would join research vessels that were looking at fish stocks – but that requires trawling. I was there to look at all the bycatch which is, of course, destroyed in the process.

One day sticks out for me. We struggled to get the trawl back on the deck because the net contained spectacular sponges that were probably hundreds of years old. These glass sponges were like enormous vases. You could sit in them, they were so big – at least a good metre across. They’re home to so many other organisms as well, such as snake stars and ice fish that hide within. Once you lose the structure that these organisms provide, you’re messing with the whole ecosystem. But, if you are going to get it protected, you’ve got to know it’s there and in those days that was the only way to do it.

Hexactinellid glass sponge — A glass sponge ‘like an enormous vase’ found in the Weddell Sea, Antarctica. Photograph: Marizilda Cruppe/Greenpeace

Then thanks to developments in technology, we could start looking at these communities in submersibles, which is non-invasive, and you get to see the whole thing in situ, which I much prefer. My first trip to the Antarctic seafloor was in 2018.

You get dropped into the water in what is essentially a tiny bubble. It can take up to 30 minutes to reach the seafloor. As you go down the light disappears – there’s a point at which you no longer see the light from above, and then all these bioluminescent animals start flashing before your eyes. A creature that may look like a gelatinous blob out of water is revealed as delicate, graceful and remarkable in the water when alive. Then you get near the seafloor and you turn on the lights and it’s an explosion of colour – it’s just specular.

Dr Susanne Lockhart and John Hocevar, Greenpeace USA’s Oceans Campaigns Director and submersible pilot, in a red submersible surfacing in Antarctica. — Lockhart, left, with John Hocevar, Greenpeace USA’s oceans campaigns director – and submersible pilot. Photograph: Marizilda Cruppe/Greenpeace

My job is to discover what is there and make a scientific case to protect a site. I am essentially looking for animals that are fragile and long-lived, and won’t recover easily if damaged by fishing gear – things like coral and sponges that are not mobile and create shelter for other organisms.

I have helped create 47 vulnerable marine ecosystems (VMEs), which equates to more than 500 sq km of seafloor now protected from commercial bottom fishing for ever. The presence of VMEs helps us make a case to create marine protected areas (MPAs) in the Southern Ocean around Antarctica. It’s a bit of a geopolitical quagmire, where some countries, namely Russia and China, disagree and so they block everything. We need a change in the political arena so we can create more MPAs and this requires more public awareness about how special these places are.

At least once every expedition I will see something that really stumps me. Without a specimen in my hand I won’t even know which phylum it’s in (that’s the one under kingdom). That’s always pretty exciting.

I feel great responsibility. I have a unique and rare experience to witness one the world’s last great wildernesses and I need to share that. I would love for people not to just think about the penguins when they think about the Antarctic.